Conventionally, a variety of filter presses have been proposed and actually used. For instance, FIG. 1 shows one of the popular filter presses of the single acting type consisting of a filter plate 1, a filter frame 2 and a filter cloth 3 adapted to be disposed between the filter plate 1 and the filter frame 2 to be clamped and compressed by them. A liquid to be treated is adapted to be supplied to the filter frame 2, and then to be passed through the filter cloth 3. The liquid is finally collected through communication ports from a recess 4 of the filter plate 1. A cake 5 of separated materials left on the filter frame 2 can be removed at the time of separation of the filter plate 1 and the filter frame 2 from each other.
Although this type of filter press provides an easy collection of the filtrated cake by separation of the filter plate 1 and the filter frame 2 from each other, the following problem is inevitably caused due to the single acting nature which relies solely on the pressure exerted on the liquid to be filtrated. Namely, as the filtrated cake caught by the filter frame 2 is accumulated as a result of a continuous operation of the filter press, a higher pressure on the liquid becomes necessary to make the liquid pass through the filter. This drastic increase of the pressure of the liquid disadvantageously causes a rapid wearing down of the piston for pressurizing the liquid and, consequently, necessitates a frequent renewing of the piston parts such as a lip of the piston.
Another disadvantage is that a repeated assembling and disassembling of the filter is necessary for performing a complete separation of the liquid and the solid, since the capacity of the filter press for housing the liquid is considerably small so as to deteriorate the performance of the filter press.
It is therefore an object of the invention, in view of the above mentioned problems inherent in the conventional filter presses, to provide a filter press which is free from these problems.
It is another object of the invention to provide a filter press capable of performing an efficient separation of the liquid and the solid material through a compression of the liquid in a radial direction of the filter cloth.
It is still another object of the invention to provide a large scale of liquid-solid separation through compression of a large volume.
It is still another object of the invention to provide a filter press which can be easily disassembled to provide a facilitated collection of the filtrated cake.